6 ms·

There is ton of overnight capacity but it’s mostly non renewables right now, which drives up your CO2 emitted per mile. We really need, in California at least,

There is ton of overnight capacity but it’s mostly non renewables right now, which drives up your CO2 emitted per mile. We really need, in California at least, to ramp up workplace charging, otherwise we’re going to have a lot of unused solar :-/.

ben_w 6y ago
While true, the plus side is EVs are still a net CO2 win even when charged by dirty fuel. As part of the same topic, I think we’re going to see PV-covered EV cars in the not too distant future; not because they don’t need charging (they’re about 10% of your instant needs on the move), but because adding PV reduces the pressure on the grid, and will significantly reduce the need to install power lines to sunlit car parks. Home, multi-storey, and hotel/motel parking will still almost certainly still need power.
- JulianMorrison 6y ago
  You're also unlikely to pick up any useful charge anywhere more northerly or where the weather tends to overcast.
  - ben_w 6y ago
    My baseline is the U.K., which is further north than any of the contiguous USA and frequently overcast.
- rapsey 6y ago
  > While true, the plus side is EVs are still a net CO2 win even when charged by dirty fuel. Are they? Does that include the manufacturing process?
  - zaroth 6y ago
    Yes it does. Payback takes a few years depending on the CO2 intensity of the electrical supply, but you do get there even with some coal in the mix. Here is a quite comprehensive analysis: https://www.nature.com/articles/s41893-020-0488-7.epdf https://www.nature.com/articles/s41893-020-0488-7.epdf Edit: you might have better luck with this link; https://www.nature.com/articles/s41893-020-0488-7.epdf?referrer_access_token=TPO4EjeSKKekNKMyogr2RNRgN0jAjWel9jnR3ZoTv0OMBHrNGD6k2npei17x4aWWLctOfIoyfalbH9WNy5EPZCOSWTbm4pfMxuvEuQUnMLszjDPeoVkBlbvKQ2-fEFv3zieSCy-tF3BHi5vbyD3jSnmeEJUBuX-CQG-8gTJdac58sREr6vVjR8UB6iaNQk3HPtlkyjQ_CrjzXvQfqj92Q-LV4hr83vGLMn59vx0SgB-LY8BnZpm4eNzpOVu1YUj-L6h5Nuin9CAfr8Z9PAnatl12HtFSH8xmBvS8ZVRHcwj02-3Co4zD4iHvLosMxgjW&tracking_referrer=www.theguardian.com https://www.nature.com/articles/s41893-020-0488-7.epdf?refer...
    - im3w1l 6y ago
      I don't have access to that article but does it take into account the notion of marginal power? That any increased load is going to be disproportionally dirty?
      - philipkglass 6y ago
        It's not a given that increased load is going to be disproportionally dirty. Wind farm output typically peaks at night. Wind is a great match for night time battery energy vehicle charging and it has the lowest life cycle CO2 footprint of any electricity source: https://en.wikipedia.org/wiki/Life-cycle_greenhouse_gas_emissions_of_energy_sources#2014_IPCC,_Global_warming_potential_of_selected_electricity_sources https://en.wikipedia.org/wiki/Life-cycle_greenhouse_gas_emis... I do like your emphasis on marginal effects. As renewables and BEVs grow it will be a balancing act to pick the most marginally effective resources for emissions abatement. California may soon reach a point where an additional dollar invested in solar doesn't abate as much CO2 as the same dollar invested in transmission, storage, or wind -- even if solar has the lowest instantaneous generation cost.
        throwawayboise 6y ago
        > Wind farm output typically peaks at night. Is this generally true, or does it depend on geography (e.g. being near the coast)? Where I am in the midwest, it seems that the air normally gets very calm after sunset.
        philipkglass 6y ago
        I think that it is generally true for land based turbines. Turbines are so tall that wind conditions at hub height can't be easily estimated by what we experience on the ground. Here's a somewhat dated study that shows hourly patterns for wind generation on the ERCOT grid in Texas, which has the largest wind fleet of any state: "The Relationship between Wind Generation and Balancing-Energy Market Prices in ERCOT: 2007–2009" https://www.nrel.gov/docs/fy11osti/49415.pdf https://www.nrel.gov/docs/fy11osti/49415.pdf See Figure 5. Hourly generation reaches a minimum from about 1:00 to 5:00 PM and reaches its maximum around 1:00 AM. Offshore wind output changes less from short term day-night cycles, and generally achieves a higher capacity factor. It is also more expensive to build than onshore wind and no large projects have yet been built for the US, though several are on the drawing board.
  - ants_a 6y ago
    Yes, but it will take a few years of driving to break even. Example calculation: https://uploads.volkswagen-newsroom.com/system/production/uploaded_files/14448/file/da01b16ac9b580a3c8bc190ea2af27db4e0d4546/Klimabilanz_von_E-Fahrzeugen_Life_Cycle_Engineering.pdf?1556110703 https://uploads.volkswagen-newsroom.com/system/production/up...
  - paul_f 6y ago
    Not sure a coal-powered car is exactly ideal. We need a better solution
- thatfrenchguy 6y ago
  They are a net CO2 win, but not enough of a win if you charge them on dirty fuel. So making sure we don't make people too relient on charging on dirty fuel is important.
- steveBK123 6y ago
  There’s some overhead to the charger-battery system to actually generate any sort of a charge. I’ve had the exact same assumption multiple times, and as soon as I do some research with the math breakdown.. its clear why we don’t see these in production yet. With current efficiency PV systems, the math requires a fairly large surface like the entire flatbed of a Cybertruck to actually generate a meaningful charge. This also requires the vehicle be parked somewhere its going to get a good amount of sun, excluding parking garages, a lot of urban areas, etc.
  - deleted 6y ago
    [deleted]
  - ben_w 6y ago
    Ok, as you’ve done the maths: what charge do you get? Not the ~10% I got from a back-of-the-envelope calculation? Model 3 is about 5m by 2m, and is apparently rated for 241 Wh/mile 4m * 2m * 1kw/m^2 * 50% * 20% = average power 800 W (50% because the panels are flat, 20% because cell efficiency) 241 Wh/mile * 60 miles/day = average usage 602 W I’m not sure what fraction of the day people drive for given that I’m not a driver, but I’m eyeballing 5-10%. I acknowledge professional drivers — taxis etc. — can’t possibly rely on PV alone, that PV can only supply a fraction of what they need (my 10% guesstimate), but I still think this should help with the general public. Or are my assumptions way off?
    - steveBK123 6y ago
      First you missed a decimal point or two here and scrambled the units of measure- “ 241 Wh/mile * 60 miles/day = average usage 602 W” The correct math is 241 Wh/mile * 60 miles/day = average usage 14,460Wh, or 14.46kWh Further answer - The consensus from people who know this better than you & I, have these cars, and in some cases have tried.. is basically - it won’t charge much, and it’s way more expensive than the electricity it is going to generate. Note there are AC-DC inverter losses of 10-20%. plus input->battery charge losses which are non-linear and very bad at the low end. For example a Tesla won’t even take a charge if the input is below the ~300-500W range in good weather. In cold weather say Northeast US winter, the floor is closer to a 1kW input as there is a heating system to get the battery put to temperature for charging that is going to eat almost all of that. https://forums.tesla.com/discussion/93521/solar-panels-on-the-roof-of-the-car-for-charging-is-it-possible https://forums.tesla.com/discussion/93521/solar-panels-on-th... https://forums.tesla.com/discussion/150998/charge-tesla-w-solar-panels-in-parking-lot https://forums.tesla.com/discussion/150998/charge-tesla-w-so...
- Tagbert 6y ago
  You are better off putting those solar panels on your home/apt roof where they can produce more power and not add to the weight of the car.
  - ben_w 6y ago
    Right now? Houses sure, but I tried to get them in my last apartment, and the answer was “no” even though I owned my own flat. (Owning a flat != owning the building the flat is in). But this is about what I expect soon-ish, and “soon-ish” both continues the cost decline of PV (including thin flexible panels that would make them suitable for more than just the Cybertruck), and also makes it likely that every roof suitable for PV will already have it (because exponential growth).
- dehrmann 6y ago
  > significantly I'm guessing you'll get no more than 400W of power on-car solar. I'm guessing 1-2 rooftop panels with a sub-optimal angel. A Model 3 uses 0.24 hWh per mile. That's 13 miles of range from baking in the sun for 8 hours? Best case?
  - snypher 6y ago
    According to ABC News, the average American drives 16 miles to work each way. I'll take a free 13 miles.
    - steveBK123 6y ago
      The problem is that it’s not free.. it’s probably $1000-2000 increase in parts to generate 50cents/day of electricity...
      - ben_w 6y ago
        Right now yes, but solar is still getting cheaper. I’m expecting it at some vague point in the not too distant future, but not in a surprise tweet from Musk tomorrow.
- eightails 6y ago
  > I think we’re going to see PV-covered EV cars in the not too distant future They're already popping up in the development stage [0]. 12 km/hr peak solar charging sounds really quite good, and I like the overall design. The company was founded by students who won the World Solar Challenge [1] in 2015, it's pretty neat to see them taking that experience and running with it. [0] https://lightyear.one/lightyear-one https://lightyear.one/lightyear-one [1] https://en.wikipedia.org/wiki/World_Solar_Challenge https://en.wikipedia.org/wiki/World_Solar_Challenge
- 542354234235 6y ago
  But solar panels you can slap on a building roof or make into covered parking will always be cheaper than form factor panels installed in the roof of a vehicle. Other than super specific fringe use cases, there is just no reason to justify installing these expensive specialty panels in cars instead of installing them at homes/workplaces/retail centers and just charging EVs at those locations. There is also the cost savings in scaling. The cost for a solar system comes down even more when a business can install a whole row of solar panel covered parking, either offer EV charging as a perk or charge for charging, and use the rest of the electricity to power normal electric operations. For the driver, buying the electricity as needed from home or work panels would always be cheaper per total watt usage than buying in-car roof panels, since again, the specialty nature of them means they will always be more expensive and less efficient than their stationary mounted counterparts. You can never scale up car roof solar because you can never install move than one car roof’s worth at a time. You also can’t ignore the inverter power loss that is much worse at the lower power a car roof system would have. Then of course you have the downsides of long term sun damage to your vehicle to get that minimal charge, instead of protected under a solar panel covered parking or in a garage with solar mounted on top. You have the higher rate of damage by being installed on a moving vehicle instead of a stationary object on a building or parking structure roof. You have the lower rate of return, since panels are rated for 20-25 plus years and most vehicles don’t stay on the road that long. You have the downside of sub optimal charging angle and all the time the vehicle spends in a parking garage during the day, as opposed to a stationary panel that is pointed at the sun 365 days a year. At the end of the day, it will always be cheaper and more efficient to have stationary solar panels. Given that most people charge their EVs overnight/during work anyway, car roof panels would only really provide value during “road trip” situations, where you are driving close to or beyond at full charge per day. Since you are only getting at best 10-15 additional miles over an entire day in the sun (and more realistically less than 10), it would do very little to reduce range anxiety. And that is not even calculating how much the additional weight of the panels would reduce range. It sounds good on paper but it is highly unlikely to translate to a real world benefit.
steveBK123 6y ago
I’m not sure that’s entirely true because you are only thinking of solar. I’d like to see daytime vs overnight generation source breakdown. Remember that hydro power doesn’t care about time of day and wind is often able to generate more overnight than during the day. Further time of use rates can be tweaked as usage & generation requires. Maybe with a lot of EVs in the future & solar installed we encourage people to charge mid-day at work or sunrise->commute start & commute end->sundown, this doesn’t work great in winter but also electric use is lower in winter so maybe it nets out.
skolos 6y ago
Not everywhere. In Texas most extra renewable capacity is actually at night since at night wind is stronger.
selectodude 6y ago
In states like Illinois with a high percentage of base load coming from nuclear and wind, charging overnight is basically free. In fact, overnight, Illinois is a net exporter of electricity.
njarboe 6y ago
Too bad California is shutting down its last nuclear power station in 2025 (which provides 10% of California's electricity) because upgrading its cooling system to meet new ocean water temperature regulations would cost on the order of $10 billion dollars.

ben_w 6y ago

While true, the plus side is EVs are still a net CO2 win even when charged by dirty fuel. As part of the same topic, I think we’re going to see PV-covered EV cars in the not too distant future; not because they don’t need charging (they’re about 10% of your instant needs on the move), but because adding PV reduces the pressure on the grid, and will significantly reduce the need to install power lines to sunlit car parks. Home, multi-storey, and hotel/motel parking will still almost certainly still need power.

JulianMorrison 6y ago
You're also unlikely to pick up any useful charge anywhere more northerly or where the weather tends to overcast.
- ben_w 6y ago
  My baseline is the U.K., which is further north than any of the contiguous USA and frequently overcast.
rapsey 6y ago
> While true, the plus side is EVs are still a net CO2 win even when charged by dirty fuel. Are they? Does that include the manufacturing process?
- zaroth 6y ago
  Yes it does. Payback takes a few years depending on the CO2 intensity of the electrical supply, but you do get there even with some coal in the mix. Here is a quite comprehensive analysis: https://www.nature.com/articles/s41893-020-0488-7.epdf https://www.nature.com/articles/s41893-020-0488-7.epdf Edit: you might have better luck with this link; https://www.nature.com/articles/s41893-020-0488-7.epdf?referrer_access_token=TPO4EjeSKKekNKMyogr2RNRgN0jAjWel9jnR3ZoTv0OMBHrNGD6k2npei17x4aWWLctOfIoyfalbH9WNy5EPZCOSWTbm4pfMxuvEuQUnMLszjDPeoVkBlbvKQ2-fEFv3zieSCy-tF3BHi5vbyD3jSnmeEJUBuX-CQG-8gTJdac58sREr6vVjR8UB6iaNQk3HPtlkyjQ_CrjzXvQfqj92Q-LV4hr83vGLMn59vx0SgB-LY8BnZpm4eNzpOVu1YUj-L6h5Nuin9CAfr8Z9PAnatl12HtFSH8xmBvS8ZVRHcwj02-3Co4zD4iHvLosMxgjW&tracking_referrer=www.theguardian.com https://www.nature.com/articles/s41893-020-0488-7.epdf?refer...
  - im3w1l 6y ago
    I don't have access to that article but does it take into account the notion of marginal power? That any increased load is going to be disproportionally dirty?
    - philipkglass 6y ago
      It's not a given that increased load is going to be disproportionally dirty. Wind farm output typically peaks at night. Wind is a great match for night time battery energy vehicle charging and it has the lowest life cycle CO2 footprint of any electricity source: https://en.wikipedia.org/wiki/Life-cycle_greenhouse_gas_emissions_of_energy_sources#2014_IPCC,_Global_warming_potential_of_selected_electricity_sources https://en.wikipedia.org/wiki/Life-cycle_greenhouse_gas_emis... I do like your emphasis on marginal effects. As renewables and BEVs grow it will be a balancing act to pick the most marginally effective resources for emissions abatement. California may soon reach a point where an additional dollar invested in solar doesn't abate as much CO2 as the same dollar invested in transmission, storage, or wind -- even if solar has the lowest instantaneous generation cost.
      - throwawayboise 6y ago
        > Wind farm output typically peaks at night. Is this generally true, or does it depend on geography (e.g. being near the coast)? Where I am in the midwest, it seems that the air normally gets very calm after sunset.
        philipkglass 6y ago
        I think that it is generally true for land based turbines. Turbines are so tall that wind conditions at hub height can't be easily estimated by what we experience on the ground. Here's a somewhat dated study that shows hourly patterns for wind generation on the ERCOT grid in Texas, which has the largest wind fleet of any state: "The Relationship between Wind Generation and Balancing-Energy Market Prices in ERCOT: 2007–2009" https://www.nrel.gov/docs/fy11osti/49415.pdf https://www.nrel.gov/docs/fy11osti/49415.pdf See Figure 5. Hourly generation reaches a minimum from about 1:00 to 5:00 PM and reaches its maximum around 1:00 AM. Offshore wind output changes less from short term day-night cycles, and generally achieves a higher capacity factor. It is also more expensive to build than onshore wind and no large projects have yet been built for the US, though several are on the drawing board.
- ants_a 6y ago
  Yes, but it will take a few years of driving to break even. Example calculation: https://uploads.volkswagen-newsroom.com/system/production/uploaded_files/14448/file/da01b16ac9b580a3c8bc190ea2af27db4e0d4546/Klimabilanz_von_E-Fahrzeugen_Life_Cycle_Engineering.pdf?1556110703 https://uploads.volkswagen-newsroom.com/system/production/up...
- paul_f 6y ago
  Not sure a coal-powered car is exactly ideal. We need a better solution
thatfrenchguy 6y ago
They are a net CO2 win, but not enough of a win if you charge them on dirty fuel. So making sure we don't make people too relient on charging on dirty fuel is important.
steveBK123 6y ago
There’s some overhead to the charger-battery system to actually generate any sort of a charge. I’ve had the exact same assumption multiple times, and as soon as I do some research with the math breakdown.. its clear why we don’t see these in production yet. With current efficiency PV systems, the math requires a fairly large surface like the entire flatbed of a Cybertruck to actually generate a meaningful charge. This also requires the vehicle be parked somewhere its going to get a good amount of sun, excluding parking garages, a lot of urban areas, etc.
- deleted 6y ago
  [deleted]
- ben_w 6y ago
  Ok, as you’ve done the maths: what charge do you get? Not the ~10% I got from a back-of-the-envelope calculation? Model 3 is about 5m by 2m, and is apparently rated for 241 Wh/mile 4m * 2m * 1kw/m^2 * 50% * 20% = average power 800 W (50% because the panels are flat, 20% because cell efficiency) 241 Wh/mile * 60 miles/day = average usage 602 W I’m not sure what fraction of the day people drive for given that I’m not a driver, but I’m eyeballing 5-10%. I acknowledge professional drivers — taxis etc. — can’t possibly rely on PV alone, that PV can only supply a fraction of what they need (my 10% guesstimate), but I still think this should help with the general public. Or are my assumptions way off?
  - steveBK123 6y ago
    First you missed a decimal point or two here and scrambled the units of measure- “ 241 Wh/mile * 60 miles/day = average usage 602 W” The correct math is 241 Wh/mile * 60 miles/day = average usage 14,460Wh, or 14.46kWh Further answer - The consensus from people who know this better than you & I, have these cars, and in some cases have tried.. is basically - it won’t charge much, and it’s way more expensive than the electricity it is going to generate. Note there are AC-DC inverter losses of 10-20%. plus input->battery charge losses which are non-linear and very bad at the low end. For example a Tesla won’t even take a charge if the input is below the ~300-500W range in good weather. In cold weather say Northeast US winter, the floor is closer to a 1kW input as there is a heating system to get the battery put to temperature for charging that is going to eat almost all of that. https://forums.tesla.com/discussion/93521/solar-panels-on-the-roof-of-the-car-for-charging-is-it-possible https://forums.tesla.com/discussion/93521/solar-panels-on-th... https://forums.tesla.com/discussion/150998/charge-tesla-w-solar-panels-in-parking-lot https://forums.tesla.com/discussion/150998/charge-tesla-w-so...
Tagbert 6y ago
You are better off putting those solar panels on your home/apt roof where they can produce more power and not add to the weight of the car.
- ben_w 6y ago
  Right now? Houses sure, but I tried to get them in my last apartment, and the answer was “no” even though I owned my own flat. (Owning a flat != owning the building the flat is in). But this is about what I expect soon-ish, and “soon-ish” both continues the cost decline of PV (including thin flexible panels that would make them suitable for more than just the Cybertruck), and also makes it likely that every roof suitable for PV will already have it (because exponential growth).
dehrmann 6y ago
> significantly I'm guessing you'll get no more than 400W of power on-car solar. I'm guessing 1-2 rooftop panels with a sub-optimal angel. A Model 3 uses 0.24 hWh per mile. That's 13 miles of range from baking in the sun for 8 hours? Best case?
- snypher 6y ago
  According to ABC News, the average American drives 16 miles to work each way. I'll take a free 13 miles.
  - steveBK123 6y ago
    The problem is that it’s not free.. it’s probably $1000-2000 increase in parts to generate 50cents/day of electricity...
    - ben_w 6y ago
      Right now yes, but solar is still getting cheaper. I’m expecting it at some vague point in the not too distant future, but not in a surprise tweet from Musk tomorrow.
eightails 6y ago
> I think we’re going to see PV-covered EV cars in the not too distant future They're already popping up in the development stage [0]. 12 km/hr peak solar charging sounds really quite good, and I like the overall design. The company was founded by students who won the World Solar Challenge [1] in 2015, it's pretty neat to see them taking that experience and running with it. [0] https://lightyear.one/lightyear-one https://lightyear.one/lightyear-one [1] https://en.wikipedia.org/wiki/World_Solar_Challenge https://en.wikipedia.org/wiki/World_Solar_Challenge
542354234235 6y ago
But solar panels you can slap on a building roof or make into covered parking will always be cheaper than form factor panels installed in the roof of a vehicle. Other than super specific fringe use cases, there is just no reason to justify installing these expensive specialty panels in cars instead of installing them at homes/workplaces/retail centers and just charging EVs at those locations. There is also the cost savings in scaling. The cost for a solar system comes down even more when a business can install a whole row of solar panel covered parking, either offer EV charging as a perk or charge for charging, and use the rest of the electricity to power normal electric operations. For the driver, buying the electricity as needed from home or work panels would always be cheaper per total watt usage than buying in-car roof panels, since again, the specialty nature of them means they will always be more expensive and less efficient than their stationary mounted counterparts. You can never scale up car roof solar because you can never install move than one car roof’s worth at a time. You also can’t ignore the inverter power loss that is much worse at the lower power a car roof system would have. Then of course you have the downsides of long term sun damage to your vehicle to get that minimal charge, instead of protected under a solar panel covered parking or in a garage with solar mounted on top. You have the higher rate of damage by being installed on a moving vehicle instead of a stationary object on a building or parking structure roof. You have the lower rate of return, since panels are rated for 20-25 plus years and most vehicles don’t stay on the road that long. You have the downside of sub optimal charging angle and all the time the vehicle spends in a parking garage during the day, as opposed to a stationary panel that is pointed at the sun 365 days a year. At the end of the day, it will always be cheaper and more efficient to have stationary solar panels. Given that most people charge their EVs overnight/during work anyway, car roof panels would only really provide value during “road trip” situations, where you are driving close to or beyond at full charge per day. Since you are only getting at best 10-15 additional miles over an entire day in the sun (and more realistically less than 10), it would do very little to reduce range anxiety. And that is not even calculating how much the additional weight of the panels would reduce range. It sounds good on paper but it is highly unlikely to translate to a real world benefit.

steveBK123 6y ago

I’m not sure that’s entirely true because you are only thinking of solar. I’d like to see daytime vs overnight generation source breakdown. Remember that hydro power doesn’t care about time of day and wind is often able to generate more overnight than during the day. Further time of use rates can be tweaked as usage & generation requires. Maybe with a lot of EVs in the future & solar installed we encourage people to charge mid-day at work or sunrise->commute start & commute end->sundown, this doesn’t work great in winter but also electric use is lower in winter so maybe it nets out.

skolos 6y ago

Not everywhere. In Texas most extra renewable capacity is actually at night since at night wind is stronger.

selectodude 6y ago

In states like Illinois with a high percentage of base load coming from nuclear and wind, charging overnight is basically free. In fact, overnight, Illinois is a net exporter of electricity.

njarboe 6y ago

Too bad California is shutting down its last nuclear power station in 2025 (which provides 10% of California's electricity) because upgrading its cooling system to meet new ocean water temperature regulations would cost on the order of $10 billion dollars.